20 THE FORCING GARDENER. JJB. fi 



all round, to the height of a yard, againft 

 the fides and ends } and this I chiefly ad- 

 Vife, on account of the value of the front 

 flue, which may be fo eafily rendered fer- 

 viceable in raifing early fallads, &c. on a 

 well-prepared border immediately adjoin- 

 ing thereto, as hinted in the note, page 19^ 



Here the furnaces are placed behind, 

 communicating firft with the front flues^ 

 which return in the back, fingly. The fur- 

 face of the bark-bed is level with the bot- 

 tom of the flues ail round, a cavity fepa- 

 rates the front flue from the bark-bed, 

 and confequently no apprehenfion of burn- 

 ing need be entertained. The inner wall 

 of the flue is a brick on edge, and for the 

 fake of ftrength, the outer wall a brick on 

 bed. 



Although in this defign the dipfions are 

 but thirty feet long each, yet wei;e a great- 

 er extent required, they might be made 

 forty, as a furnace is perfedly capable of 

 working that much, if the pit is of the 

 fame width* 



One length of a fafli is fufEcient here, 

 and they are worked in the manner of a 



common 



